Cleanup: fix printGPSCoords signature and leaks

The printGPSCoords() function returns a copied C-style string. Since
the owndership is transferred to the caller, the correct return type
is "char *" instead of "const char *".

Thus a number of casts when calling free can be removed.

Moreover a number of callers didn't free the string and thus were
leaking memory. Fix them. Ultimately we might want two versions
of the function: one for QString, one for C-style strings.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

mobile-widgets/qmlmanager.cpp

@@ -1602,9 +1602,12 @@ QString QMLManager::getGpsFromSiteName(const QString& siteName)
 	struct dive_site *ds;
 
 	ds = get_dive_site_by_name(qPrintable(siteName));
-	if (ds)
-		return QString(printGPSCoords(&ds->location));
-	return QString();
+	if (!ds)
+		return QString();
+	char *gps = printGPSCoords(&ds->location);
+	QString res = gps;
+	free(gps);
+	return res;
 }
 
 void QMLManager::setNotificationText(QString text)